Ultrabroadband FBG filters using femtosecond pulses

We report on the writing of ultrabroadband Fiber Bragg Gratings in standard telecom fibers by the use of a highly chirped first-order phase-mask in conjunction with infrared femtosecond pulses. A high reflectivity (99%) and high chirp rate (95 nm/cm) filter providing a wavelength coverage of five telecom bands (E+S+C+L+U) is demonstrated over a single 35 mm long grating obtained following an exposure time of only 30 s in a H₂-loaded SMF-28 fiber segment. This report paves the way to the development of new broadband fiber-based optical components with unique features able to provide large bandwidths and low-losses.